When executing a mission critical application (e.g., a web server or a database server) in a computer facility comprising a cluster of multiple host computers, there is typically a first host computer that is configured as a primary host and second host computer is configured as a secondary host. In some configurations, there may be multiple secondary host computers. In operation, the secondary host computer monitors the status of the of the primary host computer, and if the secondary host detects (with a high confidence) that the primary host is either down or non-responsive, the secondary host computer can take over the responsibilities of the primary host and begin functioning as the primary host.